OK f this car NO START

[ILuvPizzaTimes10]

o rpm but you sed you were getting spark? if you have spark and no injector pulse on ALLL of your injectors under crank. then its ecm?

[irockidz28]

^that...and from some personal expierience i would check grounds

had a truck that would not cold start with out a little starting fluid when it was cold..but once it was warm it would start... noticed a bad ground strap...replaced it then it fired up no problem

[KLAB]

^found some stuff on that in this thread: http://www.automotivehelper.com/topic516221.htm

I checked the PCM grounds but I'm going to check others.

Originally Posted by DemonWithin99

stop trying to diagnose it and chase th ghost just replace the damn opti already....

You think I should just go and replace the opti? That's foolish. Process to problem solving: locate issue --> fix it, dont just assume what it is (like you and many others hear LT1 issue and call out "woop must be da OPTI LOOL") and go buy a new opti and go through hell to replace it and still have the issue a lot of good that would do.

Furthermore if I do end up diagnosing a faulty opti I'll either replace it with a GM one not an auto zone junk, or dive right into an LS swap. I'm leaning towards saving $$$ replacing opti and using it to do the swap.

I have a spare opti on my shortblock btw to try...

[KLAB]

Originally Posted by SLP IROC-Z

read quick95lt1/mikev's post in this thread
http://ls1tech.com/forums/lt1-lt4-mo...-no-start.html

well where the hell is he when i need him haahaha. Why didn't he chime in on this!??

[DemonWithin99]

just busting bawlz ... but it sure would be funny if it is the problem.



(I also should stop the teasing b4 someone gets upset or something breaks)

[ILuvPizzaTimes10]

camaros and firebirds dont have the tach filter that the vette has.

[KLAB]

I thought that sounded new to me... haha I've been through like my whole service manual and never saw anything about a tach filter

[SLP IROC-Z]

just because theres no tach filter doesnt mean he shouldnt check those circuits.

[KLAB]

the injectors are NOT getting a pulse... The other day I jerry rigged an LED and resistor to see and it blinked but must have been very low voltage. Used a real NOID and NO PULSE.

[KLAB]

myth... CONFIRMED!!! My opti is toast. No pulse going from my opti to the PCM to fire the injectors.

Noid light in and scanner hooked up cranking over no injector pulse and the rpm reading stayed at 0 then randomly hit 193? Strange.. This led me to test stuff that sends signal to the injectors. Tested the ICM, good. Tried heating up the back of it imitating a hot motor with heat gun maybe the ICM was bad and only worked when it got hot. Nope. Wires from PCM, good. Grounds, good. So I got as far as suspicion that the opti wasn't giving a low res pulse or whatever the PCM needs to know to fire injectors. So I got an idea ripped the opti off my shortblock in my shed plugged that opti in grounded it and spun it by hand while cranking INJECTOR PULSEEEE! Noid lit up. So that sucks this concludes that my opti fails to send a pulse to the PCM to fire the injectors and by testing the spare opti I had seeing that it got the signal... How clearer can it get.